Comparing the Calibration and Simulation Data of the Cryogenic Dark Matter Search

Technical Report · Wed Jun 22 00:00:00 EDT 2011

DOI:https://doi.org/10.2172/1017225· OSTI ID:1017225

DiFranzo, Anthony

The Cryogenic Dark Matter Search, or CDMS, collaboration is preparing a new experiment called SuperCDMS. CDMS uses Germanium detectors to attempt the direct detection of dark matter. To do this, they measure the ionization and heat produced during an event where a WIMP scatters off of germanium crystal lattice. To prepare for the experiment the detectors are calibrated with various radioactive sources. The response of the detectors is also modeled by a Monte Carlo simulation. These simulations include modeling everything from the radiation production to the raw data collected by the detector. The experimental data will be used to validate the results of the detector simulation. This research will look only at the phonons produced during events that occur very close to the detector surface. From the raw data and simulation output three parameters will be determined: the rise time, the decay time, and time to position independence. It was found that the simulation's risetime and time to position independence was generally smaller than that of the data, while the decay time was found to be larger in the simulation than in the data. These differences show that the simulation is not complete. The difference in risetime implies that the phonons are not spread out enough when they reach the detector walls, which would be improved by a look at the Luke phonon and charge transport. The long decay time in the simulation implies that the rate phonons are being absorbed is underestimated. Finally, the small time to position independence in the simulation could be due to a low phonon scattering rate. A simple solution may be to alter the parameters that control the simulation, while still remaining physically sensible, to help match simulation and data.

• Research Organization: SLAC National Accelerator Laboratory (SLAC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 1017225
• Report Number(s): SLAC-TN-11-004
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
Astrophysics
Other
CALIBRATION
CHARGE TRANSPORT
CRYOGENICS
CRYSTAL LATTICES
DECAY
DETECTION
GE SEMICONDUCTOR DETECTORS
GERMANIUM
IONIZATION
NONLUMINOUS MATTER
PHONONS
PRODUCTION
PULSE RISE TIME
RADIATIONS
SCATTERING
SIMULATION